自定义ListView使用的Adapter

自定义ListView所用的适配器Adapter.

Adapter是用于将数据集（字符串，图片等）和视图（Textview, Image等）进行映射。

ListView的实现需要两个要素：1.数据集，2.适配器Adapter。

举一个实例说明ListView的Adapter的自定义实现。

1. 数据集

使用的是List<Map<String,String>> list

数据集元素的添加方式如下：

Map<String,String>map = newHashMap<String,String>();
map.put("name","Tom");
map.put("age",
"23");
list.add(map);

这样就在数据集中添加了一个元素了。

2. 创建适配器

public
class SelfDefineAdapter extends BaseAdapter{……}

adapter = new SelfDefineAdapter(this,list);

3. 给ListView设置适配器

listView.setAdapter(adapter);

贴上代码：

MainActivity.java

package com.nuist.selfdefineadapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ListView;

public class MainActivity extends Activity {

private ListView listView;
private List<Map<String,String>> list;
/**
* 数组names和ages是用于填充数据集list的。
*/
private String[] names = {"Tom","Jerry","Jack"};
private int[] ages = {32,4,56};

private SelfDefineAdapter adapter;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView)findViewById(R.id.list_people);
list = getList(); //数据集，一个List
adapter = new SelfDefineAdapter(this,list);  //创建适配器，传递了数据集list过去，用于映射到控件
listView.setAdapter(adapter); //为控件ListView设置适配器
}

/**
* getList()就是讲数组names和ages的内容放到了List中
* @return
*/
private List<Map<String,String>> getList(){
List<Map<String,String>> listItem = new ArrayList<Map<String,String>>();
for(int i=0;i<ages.length;i++){
Map<String,String> map = new HashMap<String,String>();
map.put("name", names[i]);
map.put("age", ages[i]+"");
listItem.add(map);
}
return listItem;
}
}

自定义的Adapter:

package com.nuist.selfdefineadapter;

import java.util.List;
import java.util.Map;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class SelfDefineAdapter extends BaseAdapter {

private List<Map<String,String>> list; //数据集
private Context context;
private LayoutInflater listInflater;  //用于视图填充器
public final class ListRowView{  //对应list_raw.xml中的两个TextView控件
TextView name;
TextView age;
}
public SelfDefineAdapter(Context context, List<Map<String,String>> list){
this.context = context;
listInflater = LayoutInflater.from(context);
this.list = list;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return list.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ListRowView listRowView = null;
if(convertView == null){
listRowView = new ListRowView();
convertView  = listInflater.inflate(R.layout.list_raw, null);
listRowView.name = (TextView)convertView.findViewById(R.id.name);
listRowView.age = (TextView)convertView.findViewById(R.id.age);
convertView.setTag(listRowView);
}else{
listRowView = (ListRowView)convertView.getTag();
}
/**
* 将数据集中的数据和控件对应起来
*/
listRowView.name.setText((String)list.get(position).get("name"));
listRowView.age.setText((String)list.get(position).get("age"));
return convertView;
}

}

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<ListView android:id="@+id/list_people"
android:layout_height="wrap_content"
android:layout_width="match_parent"
></ListView>
</LinearLayout>

list_row.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView android:id="@+id/name"
android:layout_height="wrap_content"
android:layout_width="match_parent"/>

<TextView android:id="@+id/age"
android:layout_height="wrap_content"
android:layout_width="match_parent"/>
</LinearLayout>

运行的结果：